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https://issues.apache.org/jira/browse/LUCENE-5987?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Robert Muir updated LUCENE-5987:
--------------------------------
Attachment: LUCENE-5987.patch
Here is patch with my suggestions. I didn't like having two tragicEvent methods
on IndexWriter, to me thats confusing. so the single one just unboxes
AbortingException and there is one codepath to worry about there, and for each
case.
I am still confused about the logic in various places in DocumentsWriter (I
didnt try to tackle this here). It seems wierd we are both catching
exception/handlign stuff in finally block but then "asking" the dwpt if it has
aborted. Is there a cleaner way?
I am happy AbortingException is a checked one, its a good use here. Its fine if
it nests in IndexWriter.java to be clear too. But its already a terminology
used in the codebase so i think its the right name.
> Make indexwriter a mere mortal when exceptions strike
> -----------------------------------------------------
>
> Key: LUCENE-5987
> URL: https://issues.apache.org/jira/browse/LUCENE-5987
> Project: Lucene - Core
> Issue Type: Task
> Reporter: Robert Muir
> Assignee: Michael McCandless
> Attachments: LUCENE-5987.patch, LUCENE-5987.patch
>
>
> IndexWriter's exception handling is overly complicated. Every method in
> general reads like this:
> {code}
> try {
> try {
> try {
> ...
> // lock order: COMPLICATED
> synchronized(this or that) {
> }
> ...
> } finally {
> if (!success5) {
> deleter.deleteThisFileOrThat();
> }
> ...
> }
> }
> {code}
> Part of the problem is it acts like its an invincible superhero, e.g. can
> take a disk full on merge or flush to the face and just keep on trucking, and
> you can somehow fix the root cause and then just go about making commits on
> the same instance.
> But we have a hard enough time ensuring exceptions dont do the wrong thing
> (e.g. cause corruption), and I don't think we really test this crazy behavior
> anywhere: e.g. making commits AFTER hitting disk full and so on.
> It would probably be simpler if when such things happen, IW just considered
> them "tragic" just like OOM and rolled itself back, instead of doing all
> kinds of really scary stuff to try to "keep itself healthy" (like the little
> dance it plays with IFD in mergeMiddle manually deleting CFS files).
> Besides, without something like a WAL, Indexwriter isn't really fit to be a
> superhero anyway: it can't prevent you from losing data in such situations.
> It just doesn't have the right tools for the job.
> edit: just to be clear I am referring to abort (low level exception during
> flush) and exceptions during merge. For simple non-aborting cases like
> analyzer errors, of course we can deal with this. We already made great
> progress on turning a lot of BS exceptions that would cause aborts into
> non-aborting ones recently.
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